deffinitely separate your two dragons. since the smaller female is eating well, she could be dominating the male, preventing him from wanting to eat. as you do have a large tank, and so strapped for cash that you can't take your dragon to a vet, use a divider to divide the tank in half. making sure it's not see through so neither dragon can see the other.
i would not suggest pinky mice as it may be too big for your male dragon, as he is only 14 inches long. i never heard of the stuff you bought that is suppose to increase appetites in lizard so can't say if it would be good for it or not.
parasites don't necessarily cause lathargy, but they can sap a dragon of it's appitite, nutrients from food it does eat, as well as cause it not to grow as well or to thrive. most vets only charge about 25 dollars for a fecal. i still suggest at least getting a fecal done. call the herp vets in your area and ask what they charge, you may find it isn't as expensive as you think.
you still will have to build or buy a new tank for the female, as once she outgrows the half of the 60g you need to keep the two dragons separate. she is too small and young to breed but eventually your male, once he starts to feel better, will try to breed her. females shouldn't be bred till they are at least 15months old, with 18 months or older being better. she also should weigh at least 350g before breeding. if you don't want to breed at all, they you deffinitely want to keep the dragons in separate cages permanently.
-----
PHLdyPayne